add words in sentence w/o deleting text already there

[Kristy]

The problem i am having is when i am typing a paper then
read back over it and realize that i have forgot to put
in a word, comma, etc and i try to go back to put it in
instead of it moving all of the text over it deletes what
i have already typed anyone know how to change this
setting so it wont do that. Thank you Kristy

 

[Ed]

You might have the "insert" key active. When it is on,
you type over whatever is at the place of the cursor.
Good luck. I'm posting my own challenge with Word. Maybe
you can help.